unfortunately for you
god can change natural laws at will
I've no reason to believe this to be true, and thus no unfortunate circumstance is apparent.
In any case, by your definition of the word "sex", if it's supposed to be solely for procreation (which is nonsensical on so many levels), then wearing a condom would mean it's not sex anymore. This is nonsensical, as well.
As it stands, no God can determine what words mean among the people speaking them. Only the people speaking the words mutually decide what words mean, and sex has long been mutually agreed upon to be in reference to any sort of sexual intercourse, or even any sexual activity in more recent years between two or more people. This includes heterosexual and homosexual acts.
The same is true of marriage. If us who speak English decide that marriage can be between any two people, or even any number of people, regardless of gender, then no God can tell us otherwise.